I've seen tutorials on how to make a windows usb/flash boot drive on a mac using a windows iso & bootcamp. I've also seen tutorials on how to boot a mac from a usb drive (hold down alt when booting). However what I'm trying to do is to make a windows boot drive then boot my mac from it (installing all the 'stuff') and I'm getting stuck.
I have a late 2013/early 2014 Macbook Pro w/ 8GB RAM (but only 128GB of internal SSD) hence why I need to install windows on an external drive. I'm trying to install the latest version of the windows 10 insider preview (testing the waters of windows development).
Here's where I'm getting stuck:
I've seen a tutorial of this and apparently there's supposed to be a 4th drive partition called 'BOOTCAMP' which you then format.
What I've Been Doing:
I've connected my external SSD via USB and in the Bootcamp Assistant I checked the first 2 tasks. I select the SSD and let Bootcamp do it's thing. After it finished I restarted my mac while holding down the alt key. I get the option to choose between my HD ('Macintosh HD'), a drive called 'Windows' and a drive with a name beginning with 'e' (not sure - although it's just a higher-res version of the windows drive it seems).
Choosing windows, I follow the setup instructions until I get to the part shown in the photo, so obviously I'm doing something wrong (probably those pesky partitions).
Any help is appreciated.
EDIT: I wasn't able to install windows so it is bootable from an external drive but I was able to partition my internal drive with bootcamp after reinstalling OSX, then everything else worked as intended. I hope this helps others.